ABSTRACT Support is requested for a Keystone Symposia conference entitled Modeling Viral Infections and Immunity, organized by Drs. Alan S. Perelson, Rob J. De Boer and Phillip D. Hodgkin. The conference will be held in Estes Park, Colorado from May 1-4, 2017. Viral infection modeling has provided insights into the pathogenesis and treatment of HIV, HCV, HSV-2, CMV and other viruses. It has had impact in revealing the lifespan of infected cells, how rapidly virus is produced and cleared from the circulation, and the means for evaluating the effectiveness of antiviral treatments. For example, HIV remains a global health threat and there is great interest in revealing features of the main HIV reservoir, latently infected cells and mechanisms of reducing the size of this reservoir by pharmacological means. Similar questions revolve around many other viral pathogens. Thus, this conference will take advantage of the latest modeling approaches to address gaps in our knowledge of the cell-mediated and humoral immune responses to viruses and the identifying the information needed to develop new vaccines and therapeutics. Since viral infections generally occur in tissues, the conference will discuss imaging techniques and methods of modeling and analyzing spatial infection data, the role of tissue- resident memory cells, and important features of immune regulation, such as immune exhaustion, cytokine signaling between cells, and viral subversion of innate responses and escape from adaptive responses. The conference will highlight what we believe are significant hurdles to curing viral infections and will bring together experimental virologists, physician scientists and modelers of various types and experience, groups that do not normally meet. We anticipate that this conference will foster new collaborations between experimentalists and theoreticians, and between theoreticians working on different viral infections or different aspects of viral infections, as well as help junior scientists formulate new research directions and make connections with established senior scientists. Relevance to NIAID: NIAID supports research on topics such as HIV, HCV and influenza infection and treatment. Modeling of these infections has provided and will continue to provide important information about pathogenesis, treatment strategies, drug resistance, viral evolution and vaccine strategies as well as epidemiological information about viral transmission and spread at the population level. Viral infection modeling is also being applied to emerging infections, such as Ebola and Zika virus infection and, by the time of the conference, will have provided fundamental and quantitative information about the interactions of this virus with its host, the effects of treatment and vaccine strategies. Supporting innovative modeling approaches and encouraging more quantitative modeling of biothreat agents is also under the purview of NIAID.